Process of tanning hides.



" -WIL IJIAM G; .RoAcaoF c LEATHE I Toflllwhomit'ma/ywnccrn: i

' I Be it.:known: that we,W1LLrAM G. RoAoH,

;- 1 D S AT-Es PATENT. err-10E.

INCINNATL. OHIOQANQALBERT c. ,RoAcH,

. OF NEWPORT, KENTUCKY, ASSIGNORS TOTHECINCINNATI CHROME COMPANY,

residing at Cincinnati, inthe county of Hamil't'onand-State .of'Ohio, 8JI1 dALBERT'C. 5 EROAOH, residing -:at Newport, in the county; citizens;

of Campbell andState of Kentucky, of theUnited States, have invented certain 7' new and useful Improvements in Processesofi'lanning Hides of whichythe following is a' an. improved process of tanning hidesin which. thetanning will be uniform through-- for impregnating the hidewith chromic acid. After the hides have been dehaired, batted, and washed we subject them to a bath made from four pounds of bichromate of potassium and four pounds of hydrochloric acidto. four tosix hundred pounds of water. Thisbath would be suificient. for one hundred,

, pounds ofhides, or inplace ofjthis bath we;

might use a bath offour pounds of bichro-"- three pounds of alum to the same acid, an I The hides are'left in this amount of water.

bathfrom twelve f to forty eight hours, in

direct proportion to their thickness. -After the hides have been thoroughly saturated thus they are removed from the bath and hung over horses or racks'to drain until hasrun ofi or evaporated. They are then removed from the racks, slicked out, and given a coat of glycerin. We prefer to apply the. glycerin infits undiluted commerclal form, but glycerin of a different state of purity or dilution may be used wlth good results. The amount of glycerin used is preferably slightly in excess of that whichv is absorbed by the hide under treatment. However, under the conditions of apphcation i there will beno substantial reducing action between the chromic acid and glycerin for a MPLROQESVSJ'OF"TANQNING 'HI I f i Specification of Letters Patent; Application filed fieptember 12, 1 904 Serial No.-22 4,11 7 a mate of (potassium, three pounds of'sulfuric good results.

about one-fifth of the moisture in the hides ,oF cmcmnarr-omo, i i; CORPORATION on rea ed Dec. 1906;"

considerate length of time, so that the glycerin will uniformly. penetrate-the hide before any substantial re duction takes place. This permits 1 intimate; and uniform association between theichr om'ifi-acid and glycerin before reductiom'so thatiwhenreduction does take place the chromicqoxid is uniformly-dc ositedonthe-fiber of the-hide. Thus it wi lbe seen that the two substances, chromic acid and glycerin, are'introduced into the hide in a substantiallyquiescent or non-active-chemical state and/become. intimately and uniformlyassociated together and with the-hide w fiber before the reaction between them takes place. The; hides arelthen laid in piles one upon the other; in a fiat condition and allowed to remain thusfromtwelve to fortyeight hours,-according to the thickness of the hides. Atthe end of that timethe chromic acid will have .been-throughly reduced.-- The reduction taking place uniformly throughout the hide will, cause-a uniform depositof the chromic; OXid1'OI1 the hide fibers, and consequently a uniformly-tanned leather. Then the hides 'are washed, dried, and stuffed in the usual 'manner, depending upon the kind of leather 'that, is being made. j Whilewefprefer to useglycerin; to coat the hides after they have been removed from the first bath, We mightus'e any. saccharine solution of rapid penetrating power, varying the strength of the solution according-"to the thickness of the hide and thelength of time it is allowed to remain in the bath. This saccharine solution may be made of any of the usual forms of sugar and is preferabl applied at or near-the point of saturation, a though a weaker solution may be used with which lis absorbed by the hide under treatment. The hide should be allowed to remain in the saccharine solution from ten to twenty minutes, this time likewise depending upon the thickness of the hide. ing been removed from the saccharine solu-' After havtion the hides are piled one upon the other in a flat condition to remain until the chromic In this case also the amount applied is preferably slightly in excess of that acid hasibeen reduced, which will take from two to three days. After that the hides are washed, dried, and stuffed, as aforedescribed.

We have found that with hides treated by our process the tannage or reduction of the chromic acid to chromic oXid takes place uniformly throughoiitthe hide fiber, making a hide which is firm and pliable and devoid of gristle or untanned portions, and that the exterior is not brittle or liable to crack.

We have described the ste s commencing with the application of the g ycerin or other saccharine solution as being applied to a hide after the first bath has been completed; but we have found that a hide tanned by either the usual one or two bath processes may be subjected to these steps with good results.

We claim as our invention 1. The process of tanning hides which consists in the introduction of a reducible metallic substance and glyceri into the fibers of the hide, in a substantially inactive chemical state, and then establishing "a condition under which the reaction between said substance and glycerin takes place, substantially 3 as specified.

2. The process of tanning hides which consists in the introduction of chromic acid and glycerin into the fiber of the hide, in a substantially inactive chemical state, and then establishing a condition under which the reaction between the chromic acid and glycerin takes place, substantially as specified.

3. The process of tanning hides which consists in the introduction of a reducible substance, containing the elements of a tanning matter, and a reducing agent, into the fiber of the hide in a substantially inactivelchemical state, and then stacking the hides in piles 'to establish a condition under which reduc- E051 will take place, substantially as speci- 4. The process of tanning hides which consists in the introduction of a reducible metallic compound and an organic reducing agent, into the fiber of the hide in a substantially inactive chemical state, and then stacking the hides in piles until reduction takes place, substantially as specified.

5. The process of tanning hides which consists in the introduction of chromic acid and an organic reducing agent into the fiber of the hide in a substantially inactive chemical state, and then stacking the hides in iles until reduction takes place, substantial y as specified.

6. The process of tanning hides which consists in the introduction of chromic acid and glycerin into thefiber of the hide and then stacking the hides in piles, substantially as specified.

7. The process of tanning hides which consists in the introduction of chromic acid into their fibers; then the introduction of an organic reducing agent; and then stacking the hides in piles and leaving them thus stacked until it is desired to wash and stuff them, substantially as specified.

8. The process of tanning hides which consists in the introduction of chromic acid into their fibers; then the introduction of glycerin and then stacking the hides in piles and leaving them thus stacked until it is desired to wash and stuff them, substantially as specified.

9. The process of tanning hides which consists in the introduction of chromic acid into their fibers; then coating the hides with an organic reducing agent, allowing them to stand in piles until the acid is reduced; and then finishing the hides, substantially as specified.

10. The process of tanning hides which consists in the introduction of chromic acid into their fibers; thencoating the hides with glycerin, allowing them to stand in piles until the acid is reduced; and then finishing the hides, substantially as specified.

WILLIAM Gr. ROACH. ALBERT C. ROACH. Witnesses:

W. F. MURRAY, A. MOOORMAOK. 

